sx225 stalls

[ahwee_al]

2003 sx225 runs great but will stall with the alarm buzzer beep beep beep
sometimes it will restart other times it wont
when it doesn't want to restart the fuel pump doesn't run when you turn the key on. This can happen when it is cold or hot. This did happen infrequently in the past but usually letting the motor cool down would allow you to start back up. now even leaving it overnight is no guarantee that it will start.

so far we replaced the thermostats and poppit valve. removed and cleaned all electrical ground connections. cleaned the vst tank and filter.

I'm afraid to leave the dock as I had to run several miles with my kicker the last time it did this.

does anyone have any ideas?

[boats.net]

That is definately puzzeling. When the unit won't run, check the fuel pump connection and see if you are getting power to the pump.

[Sequoiha]

When is the last time you pulled and cleaned the O2 sensor and transfer tube. the o2 sensor dictates pulse width. and can cause lots of running issues

[ahwee_al]

Thanks for your input!
Not likely an O2 sensor issue as the motor completely shuts down. The big clue is that the HP fuel pump doesn't run when the key is turned on after the motor dies. BTW I did clean the O2 sensor and usually run seafoam in every tank

[ahwee_al]

you know I have been going down the road of thinking that this was an overheat issue as the motor would usually restart after it cooled down. Now I will look at the fuel pump electrical circuit. Main relay & resistor and see if this is the problem

Thanks...al

[jb123]

yep, check rail pressure when this happens, sounds like youre gettin a ground fault
ever service the vst ???
replace or bypass check valve after lp pumps

[ahwee_al]

I have cleaned the VST tank and filter (wasn't varnished or dirty)
Unfortunately I haven't had a pressure gauge with me when it quits (usually looking for a paddle!)

my suspicion is that something is shutting down the HP fuel pump. (bad connections, bad resistor, main relay or just a bad pump)

where would you expect to find a ground fault? fuel pump??

if the check valve between the low & HP fuel pumps was blocked I could see this causing a starving of fuel to the HP pump. but would this keep the HP pump from running when the key is initially turned on??

Thanks!!! al

[Sequoiha]

With that said, there is a resistor mounted just above the air box with a black round 2 pin connector, this limits the voltage on the fuel pump at idle, i have seen these connectors with bad or corroded connections. i have never seen one fail, it is usually just loose or bad connections.

[99yam40]

Fuel pump should have 12V+ to it any time key is on, ECU controls the negative to make it run. That is why they say to check for 12 v+ at the pump connection when pump will not run.

I think I have read that if pump pulls too many amps it will overheat the ECU and cause it to turn off pump.

Something to look into

[ahwee_al]

Thanks for the info!
does anyone know what the normal current for the HP pump is?

[jb123]

think it cant exceed 5.2 A

[rodbolt17]

much above about 6 amps and the ECU over currents and shuts down.
there is NO stall alarm on a single engine rig.
however there is a LOW voltage alarm that may sound just before the ECU drops offline as well as the fuel pump and injectors.

[ahwee_al]

Thanks for your help! I pulled the main relay and put it on the bench with my meter across the contacts and energized the relay. I measured 50k ohms then I tapped it and it went down to 10 ohms. I will order one today and get back on the water!

al

[ahwee_al]

replaced the main relay ran 3 tanks of fuel without a problem

[rodbolt17]

see how easy my job is?
anyone can do it